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Fencer Vulns
medium 5.3

CVE-2025-5197 json

Regular Expression Denial of Service (ReDoS) in huggingface/transformers

published 2025-08-06 15 mo ago modified 2026-09-10 1 mo ago also GHSA-9356-575x-2w9m , PYSEC-2026-1983 , EUVD-2025-23827

cvss
5.3
version 3.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 39%
public exploits
0
none known

Summary

A Regular Expression Denial of Service (ReDoS) vulnerability exists in the Hugging Face Transformers library, specifically in the `convert_tf_weight_name_to_pt_weight_name()` function. This function, responsible for converting TensorFlow weight names to PyTorch format, uses a regex pattern `/[^/]*___([^/]*)/` that can be exploited to cause excessive CPU consumption through crafted input strings due to catastrophic backtracking. The vulnerability affects versions up to 4.51.3 and is fixed in version 4.53.0. This issue can lead to service disruption, resource exhaustion, and potential API service vulnerabilities, impacting model conversion processes between TensorFlow and PyTorch formats.

Patch / fix

  • pypi transformers 4.53.0
  • huggingface huggingface/transformers 4.53.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2025-5197 updated cvss 5.3

transformers: Transformers ReDoS Vulnerability

  • Red Hat OpenShift Lightspeed openshift-lightspeed/lightspeed-service-api-rhel9, openshift-lightspeed-tech-preview/lightspeed-rag-tool-rhel9 Red Hat AI Inference Server rhaiis/vllm-rocm-rhel9 Red Hat Ansible Automation Platform 2 ansible-automation-platform-24/de-minimal-rhel8, ansible-automation-platform-24/de-minimal-rhel9, ansible-automation-platform-24/lightspeed-rhel8, ansible-automation-platform-25/de-minimal-rhel8, ansible-automation-platform-25/de-minimal-rhel9, ansible-automation-platform-25/lightspeed-rhel8, +9 more Red Hat Enterprise Linux AI (RHEL AI) rhelai1/gemma-2-9b-it, rhelai1/bootc-amd-rhel9, rhelai1/bootc-intel-rhel9, rhelai1/gemma-2-9b-it-fp8, rhelai1/skills-adapter-v3, rhelai1/bootc-nvidia-rhel9, +24 more Red Hat OpenShift AI (RHOAI) rhoai/odh-rhel8-operator, rhoai/odh-rhel9-operator, rhoai/odh-dashboard-rhel8, rhoai/odh-modelmesh-rhel8, rhoai/odh-modelmesh-rhel9, rhoai/odh-mm-rest-proxy-rhel8, +40 more
    affected: workaround, no fix available “Fix deferred”
  • Red Hat AI Inference Server rhaiis/vllm-cuda-rhel9
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
partial
Assessed
15 mo ago

Exploit prediction

0.45% chance of exploitation in the next 30 days, higher than 39% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • huntr.com https://huntr.com/bounties/3f8b3fd0-166b-46e7-b60f-60dd9d2678bf referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.0 5.3 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
GitHub 3.0 5.3 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
OSV 3.0 5.3 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Affected packages

ecosystem package affected fixed in
pypi transformers
<4.53.0
4.53.0

Affected products

  • huggingface huggingface/transformers

Classification

Weakness
  • CWE-1333 Inefficient Regular Expression Complexity

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.